Hello Akshita 

Thanks  for choosing career360.

See I m providing u a formula to calculate the percentile if u are having ur marks with u. So if u want to know how much marks is needed for getting that percentile use that one in reverse.

A simple formula is used to determine the percentile of a candidate-

Formula: Percentile P = ( (N- your rank)/ N) x 100

(Where P stands for percentile and N is the total number of candidates appeared for the exam) (Source: careers360 Team)

After getting getting the marks to be scored calculate the questions according to the marking scheme.

Any query ping me.

Good luck for ur future